Automatic postage handling installations are known which include devices for receiving "stuffed" envelopes and for closing them immediately prior to franking. In such installations, the envelope closing devices receive the envelopes one-by-one with their flaps open, and they moisten the gummed portion of each envelope flap prior to folding it down against the body of the envelope.
The flaps are moistened by pressing them against a moistening member while successive envelopes move under drive imparted by means which act essentially on the bodies of the envelopes. In such devices, the moistening member may be constituted by an endless belt, a wick, or a rotary drum for transferring moistening liquid from a tank in which a portion of the moistening member is wetted. While moistening liquid is being transferred, the flap is kept pressed against the moistening member.
Such devices cannot be used for wetting printed labels whose glue-coated faces must be completely and uniformly wetted while their printed faces must be protected from receiving any moisture while each label advances over a moistening member.
The object of the present invention is to provide a device for selectively wetting labels that have been printed in a franking machine, said device being readily adaptable to the franking machine and providing no risk of spoiling the printing which has just been performed.